Previously, a conventional optical disc does not have certain metadata on the disc. Examples of optical discs include a compact disc (CD), a digital video disc (DVD) and a Blu-ray Disc. Metadata are data that may be used to describe or identify a recording. Accordingly, these discs cannot be recognized by referring to metadata on the disc because there is typically no metadata on the disc.
A conventional compact disc is typically recognized by reading table of contents data from the disc and using the data to lookup information in a database. U.S. Pat. Nos. 6,230,192 and 6,330,593 (the '192 and '593 patents), which are hereby incorporated by reference, provide conventional examples of such a method. The '192 and the '593 patents relate generally to delivering supplemental entertainment content to a user listening to a musical recording. Using conventional techniques, an album identifier is computed for the album being played. The album identifier may be determined based on the number and lengths of tracks on the album. The album identifier is used to retrieve, from a database, information relating to the recordings played by the user.